Smart Turboprop – A Possible A320 Successor

Abstract

Economic Top Level Requirements (TLR) for the next generation of aircraft in the class of the B737 and A320 demand a minimum of 25% fuel burn reduction. These aircraft are built to ICAO airport requirements: Wing span of less than 36 m and field length less than 1800 m. An investigation was undertaken looking at 1.) an optimized standard jet configuration violating given ICAO airport requirements, 2.) a box wing configuration respecting ICAO airport requirements, and 3.) a "Smart Turboprop" flying lower/slower, including a Strut Braced Wing (SBW), and Natural Laminar Flow (NLF). All aircraft are optimized with Differential Evolution (DE) – a Genetic Algorithm (GA). The aircraft are modeled with a spread sheet. For the "Smart Turboprop" the best configuration was found to be one with T-Tail and two engines. It minimized the Direct Operating Costs (DOC) by almost 14 % (without SBW and without NLF). The DOC reduced by 17 % if SBW and NLF were also applied. Take-off mass reduced by 24 % and cruise Mach number (not a requirement) is down to 0.51. Fuel burn benefits could also be obtained even without a new aircraft: Proposed is a gentle violation of ICAO wing span limitations. Manufacturers offering aircraft that are wing span limited and equipped with winglets should offer (as option) also a wing span increase on both tips (by about the same amount as winglet height). Benefits come, because horizontal wing growth (wing span increase) is more efficient than vertical wing growth (winglets).